Method and system for operating an injection molding machine

ABSTRACT

According to embodiments of the present invention, there is provided a method and system for operating an injection molding machine. For example, a molding system ( 100 ) to manufacture a molded article ( 103 ) in a mold-cavity system ( 200 ) by using a molding material ( 101 ) is provided. The system ( 100 ) including pressure-control system ( 126 ) coupled with the system ( 200 ); and controller ( 160 ) operatively coupling to system ( 126 ), controller ( 160 ) having controller-usable memory ( 162 ) tangibly embodying set of controller-executable instructions ( 500 ) to direct controller ( 160 ), including mold-unpack instructions ( 520 ), including instructing controller ( 160 ) to control system ( 126 ) to reduce, after solidification, at least in part, of material ( 101 ) being located in a nub region ( 214 ) of system ( 200 ), internal pressure of material ( 101 ) received in system ( 200 ) while system ( 200 ) remains isolated from stream of flowable-molding material, beyond any reduction of internal pressure in material ( 101 ) resulting from cooling of material ( 101 ), so that reduction in internal pressure of material ( 101 ) is enough to permit safe opening of system ( 200 ) while permitting safe extraction of article ( 103 ).

TECHNICAL FIELD

The present invention relates to molding systems in general, and morespecifically to a method and system for operating an injection moldingmachine.

BACKGROUND

Examples of known molding systems are (amongst others): (i) the HYPET(TRADEMARK) Molding System, (ii) the QUADLOC (TRADEMARK) Molding System,(iii) the HYLECTRIC (TRADEMARK) Molding System, and (iv) the HYMET(TRADEMARK) Molding System, all manufactured by Husky Injection MoldingSystems (Location: Canada).

U.S. Pat. No. 4,522,778 (Inventor: BACIU et al.; Published: 1985-06-11)discloses a method and apparatus for production of parts made from aplastics material using an injection press in which a mold cavity isdefined by a mold surface and a surface of a movable piston. Firstly,the plastics material is introduced into the mold cavity, and duringinjection the piston is kept stationary for a time to form a rough moldand then retracted to form a parison. Secondly, after injection has beencompleted the piston is advanced again, and maintained in position whilecooling takes place. Thirdly, the mold is opened and the part is ejectedfrom the mold cavity.

European Patent Number 244783 (Inventor: MAUS et al.; Published:1987-11-11) discloses a method and apparatus for injection compressionmolding of thermoplastic parts. Enlarged mold cavities receiveplasticized resin, and compression of the injected resin is provided bya toggle clamp assembly. Preferably, the toggle clamp assembly providesmultiple-stage compression of the resin to first redistribute the resinand vent the cavities and, second, compress the resin to compensate forcooling-induced shrinkage thereof. In the multiple cavities, because allcavities are equally compressed simultaneously, control of the moldingprocess and balancing of the mold are readily accomplished.

European Patent Number 369009 (Inventor: UEHARA et al.; Published:1990-05-23) discloses a desired quantity of a molten thermoplastic resininjected into a mold cavity which has a greater capacity than a productvolume and is set in advance to a higher temperature than thetemperature at which the thermoplastic resin starts curing under anormal pressure. The thermoplastic resin thus injected is cooled insidethe mold cavity and is pressed before it is cooled down to a temperatureat which it starts curing under a normal pressure. Due to this pressing,the glass transition point of the thermoplastic resin is shifted to ahigher temperature side and the thermoplastic resin cures during a smalltemperature drop. The thermoplastic resin is cooled in the pressed stateuntil dynamic rigidity at normal temperature and normal pressure isobtained. The thermoplastic resin is further cooled to a withdrawingtemperature and the pressure applied to the thermoplastic resin iscontrolled so that dynamic rigidity of the thermoplastic resin duringthis cooling process can be maintained at the normal temperature andnormal pressure by offsetting the rise of dynamic rigidity of thethermoplastic resin to be caused by cooling.

European Patent Number 425060 (Inventor: KASAI et al.; Published:1991-05-02) discloses a process for effecting injection molding ofplastic resin products on an injection molding apparatus including ametal mold composed of a slidable mold element and a fixed mold elementdefining together a mold cavity, an actuator for sliding the slidablemold element, and an injection means with an injection nozzlepermissible of adjusting the nozzle flow path section. The operationincludes: (i) a first molding step of injecting a molten resin into themold cavity which has been preset by the slidable mold element so as toinclude a post-compression margin to be compressed afterwards in asecond molding step, to effect the injection under a reduced moldingpressure, while causing a temperature elevation and, thus, a viscosityreduction of the molten resin, until the mold cavity has been filled up,and (ii) a second molding step of compressing the resin so charged inthe mold cavity by operating the slidable mold element to compress thecharged resin to compensate said post-compression margin, so as to allowan effective pressing force to be imposed onto the charged resin withinthe mold cavity also after the mold gate has been sealed.

European Patent Number 593308 (Inventor: HENDRY; Published: 1994-04-20)discloses a mold apparatus and method to form a solid injection moldedplastic part. The mold portions of the mold apparatus are closed,charges of molten thermoplastic and pressurized gas are sequentiallyinjected into a mold cavity, and the mold portions are sequentiallyseparated and closed. The pressurized gas forces the hot plastic awayfrom one mold half and against the other mold half, and separation ofthe mold portions ensures uniform distribution of the pressurized gasbehind the hot plastic, which pressure is maintained during cooling.

Depending on the application, the plastic completely packs the cavity,fills but does not pack the cavity, and the mating faces can be abuttedor maintained partially separated when the mold portions close. A gasseal is formed by the plastic to prevent gas in the mold cavity fromreaching the finished exterior surface of the part during shrinkage ofthe plastic.

European Patent Number 597108 (Inventor: MORIKITA; Published:1994-05-18) discloses a localized pressurizing type injection moldingmachine for applying various processes to moldings during aninjection-molding cycle; the injection molding machine can apply variousprocesses to the moldings after the injection molding process.

European Patent Number 944466 (Inventor: HEHL; Published: 1999-09-29)discloses a process for manufacturing injection moldings in an injectionmolding machine for processing plasticized masses, in which a regulatedsubsequent pressure is applied by the injection molding unit. At leastin the areas of the molding away from the sprue, the subsequent pressureis generated by a regulated volume alteration of the mold cavity. Thesubsequent pressure can be distributed during the subsequent pressurephase even in the case of complex moldings.

European Patent Number 1343621 (Inventor: WEINMANN; Published:2003-09-17) discloses controlled correction of possible quantitativeerrors in the production of optical data supports. The cavity of themold is only partially filled prior to the stamping phase. It is thesubsequent stamping that is used to complete the filling process bymoving one mold half. In the first phase of stamping or compressing themelt, the pressure is detected in defined positions of the molds or at adefined point in time and any deviation from a predetermined setpressure value is corrected by the immediate introduction of a movementchange in the stamping process. By acting on the pressure conditions inthe mold cavity, it is possible to influence the backflow before thesprue is set, in terms of a set weight value of the finished datasupport.

PCT Patent Application Number WO/2007/039766 (Inventor: CLARKE;Published: 2007-04-12) discloses a mold for mounting between relativelymovable platens of an injection molding press for injection impactcompression molding of an article. The mold comprises a cavity plateformed with a depression, a core plate having a projecting core at leastpart of the outer surface of which is cylindrical, and a closure platemovable relative to the core plate and the cavity plate, and a surfacein sealing contact with the cylindrical outer surface of the core. Alocking mechanism is provided to lock the closure plate relative to thecavity plate while permitting the core plate to move relative to thecavity plate.

U.S. Pat. No. 7,293,981 (Inventor: NIEWELS; Published: 2007-11-13)discloses a method and apparatus for compressing melt and/orcompensating for melt shrinkage in an injection mold. The apparatusincludes a cavity mold portion adjacent a cavity plate, a core moldportion adjacent a core plate, a mold cavity formed between the moldportions, and at least one piezo-ceramic actuator disposed betweeneither or both of the core plate and the core mold portion and thecavity plate and the cavity mold portion. A controller may be connectedto the at least one piezo-ceramic actuator to activate it, therebycausing the mold cavity volume to decrease, compressing the melt.

United States Patent Application Number 2008/0026239 (Inventor: BALBONI;Published: 2008-01-31) discloses a preform that is formed by an upperneck which maintains unchanged its form in the final object and a hollowbody, joined to the neck. The method foresees the insertion, within amatrix cavity, of a metered body of polymeric material whose mass ismetered according to a reference value, and the subsequent pressureinsertion of a punch within the matrix cavity until it closes the mold'smolding chamber, the punch conferring the shape to the inner surface ofthe preform and the matrix having an inner surface which confers theshape to the outer surface of the preform. In the molding of thepreform, the error of the mass of the metered body with respect to thereference value is distributed in the hollow body, which undergoes asubsequent hot deformation until it achieves the final shape. In themold, the matrix comprises at least one deformable wall whose innersurface defines at least part of the inner surface of the matrix partintended to give form to the hollow body of the preform, said deformablewall having, at least in part, a relatively thin thickness which permitsit to be elastically deformed under the pressure of the polymericmaterial in the final preform molding step, thereby varying thethickness of the hollow body.

SUMMARY

The inventors believe that the persons of skill in the art do not fullyunderstand the problem associated with the state of the art. Thefollowing description provides an understanding of the problem and thesolution provided by the aspects of the present invention.

FIG. 1 depicts a schematic representation of a graph 10 having known PVTcurves 16, 18 of a known PET resin. It will be appreciated that the PVTcurves 16, 18 are provided by way of example, and that the presentinvention is not necessarily limited to any particular PVT per se or anyPVT curve for that matter, and that the present invention is applicableto any resin material where density of the resin changes withtemperature. PVT stands for pressure, volume, and temperature. PET isthe common name for a unique plastic belonging to the polyester family.PET polyester is formed from ethylene glycol (EG) and terephthalic acid(TPA), sometimes called purified terephthalic acid or PTA. PET's fullchemical name is polyethylene terephthalate. The PET bottle is themodern, hygienic package of choice for many food products—particularlycarbonated soft drinks and water.

The graph 10 includes a temperature axis 12 aligned along a horizontaldirection of the graph 10 (that is, located along the bottom side of thegraph 10) and increasing in magnitude from the left side to the rightside of the graph 10. The graph 10 also includes a specific volume axis14 aligned along a vertical direction of the graph 10 (that is locatedalong the left side of the graph 10) and increasing in magnitude fromthe bottom side to the top side of the graph 10. The PVT curve 16represents the characteristics (that is, the temperature and volumecharacteristics) of the known PET resin for a relatively lower internalpressure of the known PET resin. The PVT curve 18 represents thecharacteristics of the PET resin for a relatively higher internalpressure of the PET resin. It will be appreciated that the curves 16 and18 usable for any type of pet resin.

FIG. 2 depicts a schematic representation of a graph 20 having a knownmolding cycle 30 superimposed on modified PVT curves 26, 28 of the PETresin of FIG. 1. It will be appreciated that the graph 20 depictsflipped versions of the curves 16, 18 depicted in FIG. 1. Specifically,the modified PVT curves 26, 28 of FIG. 2 are the flipped versions (thatis, flipped side to side) of the curves 16, 18 of FIG. 1, respectively.The arrangement depicted in FIG. 2 permits the depiction of time asincreasing from the left side to the right side of the graph 20, andthat the known cycle of a known molding machine may be better understoodwhen time is depicted in this fashion. The graph 20 includes a time axis18 aligned along a horizontal direction of the graph 20 (that is,located along the bottom side of the graph 20) and increasing from theleft side to the right side of FIG. 2. The graph 20 also includes thespecific volume axis 14 aligned along a vertical direction of the graph20 (that is, located on the left side of the graph 20), and increasingfrom the bottom side to the top side of FIG. 2. The graph 20 alsoincludes the temperature axis 12 aligned the horizontal direction of thegraph 20 (that is, located along the top side of the graph 20), andincreasing from the right side to the left side of FIG. 2.

A known cycle time or operation 30 of a known molding system includes(more or less): an operation 31, an operation 32, an operation 33, anoperation 34, an operation 35, an operation 36, an operation 37, and anoperation 38. The operations 31 to 38 are depicted along the top side ofFIG. 2. The modified PVT curve 28 is used to describe thecharacteristics of the known PET resin during the operations 31, 32, 33,34 and 35. The characteristics of the PET resin during operation 36 isdescribed by a horizontally aligned line extending between a point 21and a point 22, which represent terminus points for a beginning and anending of the operation 36. The horizontal line (that extends betweenthe point 21 and the point 22) is used because a volume of a mold cavitydoes not increase or decrease during the operation 36, and therefore thevolume of the molten resin in the mold cavity does not change during theoperation 36. The modified PVT curve 26 is used to describe thecharacteristics of the known PET resin during operations 37 and 38.

The operation 31 includes closing a mold cavity. The operation 32includes locking the mold cavity shut and pressurizing a clamp assemblyso as to apply clamp tonnage to the mold assembly. The operation 33includes injecting melted resin into the mold cavity volume of the moldassembly; it will be appreciated that the operation 33 is sometimesknown as the “fill” cycle. The operation 34 includes slowly adding themelted resin to maintain a full cavity volume; it will be appreciatedthat the operation 34 is also known as the “hold” cycle. The operation34 provides compensation for the pressure change of the melt in the moldcavity as the temperature of the resin or melt drops; specifically, asthe temperature drops the tendency is for the pressure to drop, but theoperation 34 is used to maintain or control (or may increase) thepressure of the molten resin during the operation 34. This arrangementresults in increased density by pushing more of the melt into the moldcavity.

Typically, at the end of the hold cycle or the operation 34, theoperation 35 is executed; the operation 35 includes shutting off themold cavity or isolating the mold cavity; the operation 35 is sometimesreferred to as the “shut-off cycle” (that is, the time taken to closethe mold gate, which is expected to be a very short duration). Theoperation 35 includes moving a valve stem into a mold gate that leadsinto the mold cavity, and the valve stem is used to stop furthermovement of the molten resin into and out from the mold cavity (via themold gate).

The operation 36 permits the molten resin in the mold cavity to cooldown for a period of time; the operation 36 is commonly known as the“cool” cycle, in which the molded part is cooled while it remains heldin the mold assembly. During the operation 36, the mold gate (sometimescalled the “gate nub”) is allowed to freeze. As the molten resin coolsdown and the internal pressure remaining within the molten resin isreduced, but the density of the molten resin remains the same becausethe mass of the molten resin and the volume of the molten resin do notchange (since the mold cavity is isolated from the upstream melt as aresult of the valve stem blocking the mold gate.

The operation 37 includes depressurizing a clamp assembly and unlockinga mold assembly. Since the internal pressure of the resin in the moldcavity has reduced to near zero or preferably zero pressure, there isvery little or no danger of undesired or inadvertent (unwanted) openingof the mold assembly (this is the preferred situation so that the moldedarticle is not inadvertently damaged by allowing the mold assembly topop open under pressure); in this manner the mold assembly is safelyopened. The operation 38 includes removing the molded article formed inthe mold cavity, and then passing the molded article to a post moldcooling apparatus for further temperature reduction if so desired.

It will be appreciated that the PVT curves and the operations of thecycle 30 are not accurately drawn, but were drawn for illustrativepurposes for ease of explaining the concepts. It will be appreciated,for example, that typically, (i) the amount of time for the operation 34(hold cycle) is approximately equal to three times longer than the timerequired for the operation 36 (cool cycle), and (ii) the time for theoperation 33 (injection cycle) plus the time for the operation 36 (coolcycle) is approximately equal to the time for the operation 34 (holdcycle).

The inventors believe that the aspects of the present invention providea technical solution to the problem at hand. Specifically, the problemat hand is believed to pertain to cycle time, and more specifically itis believed to be about reducing cycle time. A reduction of even afraction of a one second represents a significant improvement for aninjection molding system used to manufacture PET preforms. It isbelieved that the cycle time of the injection molding system can besignificantly reduced by using the aspects of the present invention.

The inventors have arrived at an understanding that the cool time duringthe operation 36 disadvantageously adds a substantial portion of time tothe cycle time of the injection molding system; the inventors believethat the operation 36 serves several functions. A typical PET preformrequires (for example) approximately 1.5 seconds of cool cycle for atwelve second total cycle time, which represents 12.5% of the totalcycle time of the injection molding system. The functions provided bythe operation 36 are as follows: (i) freezing off the mold gate area(sometimes called a gate nub) of the preform, and (ii) reducing aninternal pressure of the PET perform, so that the mold assembly may beopened safely (that is, without inadvertently damaging the molded partor perform in specific and/or the mold assembly as well).

The inventors believe that the solution to the problem of reducing thecycle time is to reduce or (more preferably) overlay the time used forthe operation 36 (that is, the cool cycle) by having othermolding-system operations execute, at least in part, the functionsassociated with operation 36. This feat or arrangement is accomplishedby managing the internal pressure of the PET perform (that is, themolded article) preferably through physical methods, such as alteringthe effective volume of a mold cavity to manipulate an internal pressureof the molten resin received in the mold cavity while the mold cavityremains in an isolated condition.

The inventors believe that the state of the art does not overlay theoperation 34 and the operation 36, and the aspects of the presentinvention is to overlay the operation 34 and the operation 36 so thatthe operation 36 is carried out in parallel with at least a portion ofthe operation 34. The overlaying of operation 34 and operation 36requires a modification of the operations 34, 36. Namely, pressurecontrol during operation 34 has to be done with another device acting onthe pressurized melt held in the mold assembly. Decompression at the endof the operation 36 needs to be provided by a different mechanism thanthe natural change in density of the resin as a function of cooling the“locked-in” material.

The inventors believe that the technical advantage of the aspects of thepresent invention is a reduction in an overall cycle time of theinjection molding system.

In accordance with a first aspect of the present invention, there isprovided a molding system being configured to manufacture a moldedarticle in a mold-cavity system by using a molding material, the moldingsystem including: a pressure-control system being coupled with themold-cavity system; and a controller operatively coupling to thepressure-control system, the controller having a controller-usablememory tangibly embodying a set of controller-executable instructionsbeing configured to direct the controller, the set ofcontroller-executable instructions including: mold-unpack instructions,including instructing the controller to control the pressure-controlsystem to reduce, after solidification, at least in part, of the moldingmaterial being located in a nub region of the mold-cavity system,internal pressure of the molding material received in the mold-cavitysystem while the mold-cavity system remains isolated from a stream offlowable-molding material, beyond any reduction of the internal pressurein the molding material resulting from cooling of the molding material,so that the reduction in the internal pressure of the molding materialis enough to permit safe opening of the mold-cavity system whilepermitting safe extraction of the molded article from the mold-cavitysystem.

In accordance with a second aspect of the present invention, there isprovided a method of operating a molding system being configured tomanufacture a molded article in a mold-cavity system by using a moldingmaterial, the molding system having a pressure-control system beingcoupled with the mold-cavity system, the method including: controllingthe pressure-control system to reduce, after solidification, at least inpart, of the molding material being located in a nub region of themold-cavity system, internal pressure of the molding material receivedin the mold-cavity system while the mold-cavity system remains isolatedfrom a stream of flowable-molding material, beyond any reduction of theinternal pressure in the molding material resulting from cooling of themolding material, so that the reduction in the internal pressure of themolding material is enough to permit safe opening of the mold-cavitysystem while permitting safe extraction of the molded article from themold-cavity system.

According to another aspect of the present invention, there is providedmolding system being configured to manufacture a molded article by usinga molding material. The molding system comprises a mold-cavity systemfor forming, in use, the molded article; the mold-cavity systemincluding: a primary parting line defined between a cavity portion and aneck portion 206 and; a secondary parting line defined between the neckportion and a top portion; a controller operatively coupling to the amold-moving actuator, the controller having a controller-usable memorytangibly embodying a set of controller-executable instructions beingconfigured to direct the controller, the set of controller-executableinstructions including a mold open instruction configured to causeinitial separation of the top portion and the neck portion relative tothe secondary parting line, while keeping the primary parting lineun-opened, while maintaining at least some clamp force.

According to yet another broad aspect of the present invention, there isprovided a molding system being configured to manufacture a moldedarticle by using a molding material. The molding system comprises amold-cavity system for forming, in use, the molded article; themold-cavity system including: a stationary-mold assembly and amovable-mold assembly, defining therebetween a mold cavity; themovable-mold assembly including: a base portion, a top portion, a neckportion; a core portion, the stationary-mold assembly including: acavity portion, and a gate portion; a controller operatively coupling tothe a mold-moving actuator, the controller having a controller-usablememory tangibly embodying a set of controller-executable instructionsbeing configured to direct the controller, the set ofcontroller-executable instructions including a mold open instructionconfigured to cause relative movement between the core portion and thecavity portion by a distance sufficient to displace the totality ofmolecules of plastic of the molded article that abut with the coreportion from their relative positioning during a process cycle, thedisplacement being in substantially the same direction, whilemaintaining at least some of the clamping force.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the exemplary embodiments of the presentinvention (including alternatives and/or variations thereof) may beobtained with reference to the detailed description of the exemplaryembodiments of the present invention along with the following drawings,in which:

FIG. 1 depicts the schematic representation of the graph 10 having knownPVT curves 16, 18 of the known PET resin;

FIG. 2 depicts the schematic representation of the graph 20 having theknown cycle time 30 superimposed on the modified PVT curves 26, 28 ofthe PET resin of FIG. 1;

FIG. 3 depicts a schematic representation of a molding system 100 inaccordance with a first non-limiting embodiment;

FIG. 4 depicts a schematic representation of a mold-cavity system 200used in the molding system 100 of FIG. 3;

FIGS. 5A, 5B, 5C, 5D, 5E depict additional schematic representations ofthe mold-cavity system 200 of FIG. 4;

FIGS. 6A, 6B, 6C, 6D, 6E, 6F, 6G depict schematic representations of apressure-control system 126 used in the molding system 100 of FIG. 3;

FIG. 7 depicts a schematic representation of a set ofcontroller-executable instructions 500 having instructions for operatingthe molding system 100 of FIG. 3; and

FIGS. 8A, 8B depict schematic representations of graphs 401 and 501,respectively, having a cycle time 499 and a cycle time 599,respectively, superimposed on modified PVT curves 26, 28 of the PETresin of FIG. 2; and

FIGS. 9A and 9B are schematic representations of the mold cavity system,implemented in accordance with another non-limiting embodiment.

FIGS. 10A and 10B are schematic representations of the mold cavitysystem, depicting the effect of executing the pre-eject function.

The drawings are not necessarily to scale and are sometimes illustratedby phantom lines, diagrammatic representations and fragmentary views. Incertain instances, details that are not necessary for an understandingof the embodiments or that render other details difficult to perceivemay have been omitted.

REFERENCE NUMERALS USED IN THE DRAWINGS

The following is a listing of the elements designated to each referencenumerals used in the drawings:

10 graph 16 known pvt curves 18 known pvt curves 20 graph 26 modifiedpvt curve 28 modified pvt curve 30 known cycle time 36 operation 100molding system 101 molding material 102 stationary platen 103 moldedarticle 104 movable platen 106 platen bars 107 nub portion 108 group ofcontrollable systems 109 parting line 120 platen actuator 121 bar locks122 clamp assemblies 124 mold-cooling system 126 pressure-control system128 melt-preparation system 140 hopper 141 feed throat 142 barrelassembly 143 heater assembly 144 machine nozzle 145 screw assembly 146screw drive 150 housing 151 hydraulic piston 152 chamber 153 stop 154seal 156 link 157 wedge 158 coupler 160 controller 162 controller-usablememory 200 mold-cavity system 201 stationary-mold assembly 202 baseportion 203 movable-mold assembly 204 top portion 206 neck portion 208core portion 210 cavity portion 212 gate portion 213 mold cavity 214 nubregion 216 mold gate 222 parting line 224 witness line 226 split line240 core-cooling circuit 241 cooling tube 242 cavity-cooling circuit 244nub-cooling circuit 246 cooling tube 247 rib assembly 249 jacketassembly 251 shoulder portion 252 spring 253 bottom surface 254 bolt 255mounting bore 256 bottom face 257 tube mount 258 tube-receiving bore 260plate assembly 261 tip 264 locating device 265 wedge-receiving groove266 surface 267 wedge body 268 wedge groove 269 link body 270 link head271 link shoulder 272 housing cover 273 plate body 274 wedge cavity 275cooling circuit 276 plug 300 hot-runner system 401 graphs 412temperature axis 414 specific volume axis 418 time axis 420 graph 421point 423 point 425 point 430 operation 431 operation 432 operation 433operation 434 operation 435 operation 436 operation 437 operation 438operation 439 region 441 region 443 amount of time 445 time 480 moldingoperation 499 cycle time 500 set of controller-executable instructions501 graphs 502 melt-preparation instructions 504 mold-close instructions506 mold-lock instructions 508 tonnage-engage instructions 510melt-stream connection instructions 512 mold-injection instructions 514mold-pack instructions 516 melt-stream disconnection 518 heat-reductioninstructions instructions 519 time axis 520 mold-unpack instructions 521point 522 tonnage-disengage instructions 523 point 524 mold-unlockinstructions 525 point 526 mold-open instructions 530 hold instructions531 compensation instructions 532 mold-volume increase 540 mold-volumereduction instructions instructions 542 mold-volume increase 543 amountof time instructions 545 time 580 aggressive cycle operation 590 firstnon-limiting variation 592 second non-limiting variant 599 cycle time

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

FIG. 3 depicts the schematic representation of the molding system 100.It will be appreciated that the molding system 100 includes componentsthat are known to those skilled in the art, and these known componentswill not be described here; these known components are described, atleast in part, in the following reference books, for example: (i)“Injection Molding Handbook” authored by OSSWALD/TURNG/GRAMANN (ISBN:3-446-21669-2), (ii) “Injection Molding Handbook” authored by ROSATO ANDROSATO (ISBN: 0-412-99381-3), (iii) “Injection Molding Machines” 3rdEdition authored by JOHANNABER (ISBN 3-446-17733-7) and/or (iv) “Runnerand Gating Design Handbook” authored by BEAUMONT (ISBN 1-446-22672-9).

The molding system 100 is configured to manufacture a molded article 103by using a mold-cavity system 200 and using a molding material 101. Themold-cavity system 200 includes a stationary-mold assembly 201 and amovable-mold assembly 203. Details for the mold-cavity system 200 aredepicted in FIG. 4. The molding system 100 includes (but is not limitedto): (i) a hot-runner system 300, (ii) a stationary platen 102, (iii) amovable platen 104, (iv) platen bars 106, (v) a group of controllablesystems 108, and (iv) a controller 160. The group of controllablesystems 108 includes (but is not limited to): (i) a platen actuator 120,(ii) bar locks 121, (iii) clamp assemblies 122, (iv) a mold-coolingsystem 124, (v) a pressure-control system 126 and, (vi) amelt-preparation system 128 (also called an extruder). The components ofthe mold-cooling system 124 are depicted in FIG. 4. The components ofthe pressure-control system 126 are depicted in FIG. 6. The hot-runnersystem 300 is coupled with the stationary-mold assembly 201. Thestationary platen 102 is configured to support the hot-runner system 300and the stationary-mold assembly 201. The movable platen 104 isconfigured to support the movable-mold assembly 203, and is movablerelative to the stationary platen 102. The platen bars 106 operativelyextend between the stationary platen 102 and the movable platen 104. Theplaten actuator 120 is coupled with the movable platen 104. The barlocks 121 lockably couple the platen bars 106 with the movable platen104. The clamp assemblies 122 are coupled with the platen bars 106. Theclamp assemblies 122 are configured to apply a clamp tonnage to theplaten bars 106. The mold-cooling system 124 is configured to couplewith the mold-cavity system 200. The details for the pressure-controlsystem 126 are depicted in FIG. 6. The pressure-control system 126 isconfigured to couple with the mold-cavity system 200.

The melt-preparation system 128 is configured to couple with themold-cavity system 200. The melt-preparation system 128 includes (but isnot limited to): a hopper 140, a feed throat 141, a barrel assembly 142,a heater assembly 143, a machine nozzle 144, a screw assembly 145, and ascrew drive 146. The hopper 140 receives solid particles of resin. Thefeed throat 141 connects the hopper 140 to the barrel assembly 142. Theheater assembly 143 is connected with the barrel assembly 142. Themachine nozzle 144 connects the barrel assembly 142 with the hot-runnersystem 300. The screw assembly 145 is received in the barrel assembly142 and the screw drive 146 is connected with the screw assembly 145. Inoperation, the screw assembly 145 prepares the melt and injects the meltunder pressure through the machine nozzle 144 and into the hot-runnersystem 300, and then the hot-runner system 300 distributes the melt intorespective mold cavities defined in the mold-cavity system 200.

The controller 160 is operatively coupling to the group of controllablesystems 108. The controller 160 has a controller-usable memory 162tangibly embodying a set of controller-executable instructions 500 thatare configured to direct the controller 160 to control instructions ofthe molding system 100. The set of controller-executable instructions500 are depicted in FIG. 7.

FIG. 4 depicts the schematic representation of the mold-cavity system200 used in the molding system 100 of FIG. 3. The mold-cavity system 200includes the stationary-mold assembly 201 and the movable-mold assembly203. The movable-mold assembly 203 includes a base portion 202, a topportion 204, a neck portion 206, and a core portion 208. Mold-movingactuators (not depicted) are connected with the components of themovable-mold assembly 203. The stationary-mold assembly 201 includes acavity portion 210, a gate portion 212, a nub region 214, and a moldgate 216. Between the neck portion 206 and the top portion 204 there isa parting line 222. Between the cavity portion 210 and the neck portion206, there is a witness line 224. Between the cavity portion 210 and thegate portion 212 there is a split line 226. Between the top portion 204and the core portion 208 there is a split line.

The mold-cooling system includes: a core-cooling circuit 240, acavity-cooling circuit 242, and a nub-cooling circuit 244. Thecore-cooling circuit 240 includes a cooling tube 241, an inlet 243formed at the end of the cooling tube 241, and an outlet 245 formedbetween the outer surface of the cooling tube 241 and the base portion202. The cooling tube 241 extends into the interior of the core portion208 to an area located near the nub region 214. A cooling fluid, such aswater, flow from the inlet 243 to the tip of the cooling tube 241 andstrikes the core portion 208 that is located near the nub region 214,and flows back to the outlet 245 between the outer surface of thecooling tube 241 and the core portion 208 and the base portion 202. Thecavity-cooling circuit 242 includes cooling tube 246, a rib assembly247, and a jacket assembly 249. The rib assembly 247 includes a set ofribs extending outwardly from the cavity portion 210. The jacketassembly 249 is received overtop of the rib assembly 247 (the jacketassembly 249 is not depicted along the top side of the cavity portion210 for illustrative purposes). The cooling tube 246 is defined by theouter surface of the cavity portion 210, the rib assembly 247 and thejacket assembly 249. The nub-cooling circuit 244 includes a passagewaydefined in the gate portion 212.

It will be appreciated that a mold cavity 213 is formed within themold-cavity system 200, and the mold cavity 213 is formed as a result ofthe relative arrangement of the parts of the mold-cavity system 200, asthe relative placement of the core portion 208, the cavity portion 210,the gate portion 212, etc.

The molded article 103 (depicted as a PET preform) includes a partingline 109 formed as a result of the witness line 224 during themanufacturing of the molded article 103. The molded article 103 alsoincludes a nub portion 107 that was formed as a result of the nub region214.

FIGS. 5A, 5B, 5C, 5D, 5E depict the additional schematic representationsof the mold-cavity system 200 of FIG. 4.

FIG. 5A depicts the schematic representation of the mold-cavity system200 having the molding material 101 after the gate is shut, and the nubregion is beginning to freeze.

FIG. 5B depicts the schematic representation of the mold-cavity system200 adjusted to reduce the internal pressure of the molten resin in themold cavity after the nub region has frozen sufficiently enough.Depicted is an example of how the internal pressure of the molten resinwas reduced, which is by moving the core portion 208 to the left side ofthe FIG. 5B. It should be noted that the actual movement of the coreportion 208 is exaggerated in FIG. 5B for illustration purposes. Withincertain examples of implementation of embodiments of the presentinvention, it is expected that the movement can be within about 0.5 mm.In other embodiments of the present invention, the movement can bewithin about 0.2 mm to about 0.7 mm range. In other applications, therange of movement can be different and can be selected based on some orall of the initial pressure within the molded article 103, volume of themolded article 103 and the desired pressure drop to be obtained byimplementing embodiments of the present invention. Once the internalpressure is reduced to a much lower pressure than what is associatedwith FIG. 5A (preferably zero pressure), the mold-cavity system 200 isopened as soon as possible because the molded article 103 in the moldcavity is still somewhat warm, so it would be advantageous at this timeto permit the molded article 103 to be further cooled off by apost-cooling apparatus (not depicted but known).

FIG. 5C depicts an exploded perspective view of the mold-cavity system200 of FIG. 4. The core portion 208 includes a shoulder portion 251 thatextends radially outward from a longitudinal axis of the core portion208. A spring 252 is positioned between the shoulder portion 251 of thecore portion 208 and a bottom surface 253 of the top portion 204. Forconvenience, the spring 252 forms a disk shape with a passageway definedthrough the central axis of the spring 252, and the central passagewayof the spring 252 receives the core portion 208. A bolt 254 ispositioned near a mounting bore 255. The bolt 254 is used to mount orcouple the top portion 204 to a plate assembly 260 (the plate assembly260 is depicted in FIG. 6A). In operation, (i) the pressure-controlsystem 126 is used to apply a force to the core portion 208 and theforce is large enough to overcome the biasing effect of the spring 252,so that in effect the core portion 208 is actuatably moved or translatedtoward the top portion 204, and (ii) the pressure-control system 126stops applying the force to the core portion 208 so that the spring 252is then used to move the core portion 208 away from the top portion 204.The manner in which the pressure-control system 126 is connected withthe core portion 208 is depicted in FIG. 6C.

FIG. 5D depicts a cross-sectional perspective view along thelongitudinal axis of the mold-cavity system 200 of FIG. 4. The spring252 is positioned between the bottom surface 253 of the top portion 204and the shoulder portion 251 of the core portion 208. The spring 252abuts the bottom surface 253 of the top portion 204 and the shoulderportion 251 of the core portion 208.

FIG. 5E depicts a cross-sectional view through a longitudinal axis ofthe core portion 208 of the mold-cavity system 200 of FIG. 4. The coreportion 208 includes a bottom face 256 (which is tapered or cammed). Thebottom face 256 is used to interface with the pressure-control system126, which is depicted in FIG. 6D. The core portion 208 defines atube-receiving bore 258 that is configured or sized to receive thecooling tube 241. The tube-receiving bore 258 securely receives a tubemount 257, and the cooling tube 241 is connected to the tube mount 257.The tube mount 257 securely positions the cooling tube 241 in thetube-receiving bore 258 of the core portion 208. A plug 276 is securelyreceived at the end of the tube-receiving bore 258, and the plug 276 isoffset from the tube mount 257. Between the tube-receiving bore 258 andthe plug 276 there is a cooling inlet 259 that receives a cooling fluid(such as water), and the cooling fluid is made to flow into the coolingtube 241 and toward a tip 261 (depicted in FIG. 5D) of the core portion208. By way of example, the bottom face 256 has a five degree taper.

FIGS. 6A, 6B, 6C, 6D, 6E, 6F, 6G depict the schematic representations ofthe pressure-control system 126 used in the molding system 100 of FIG.3.

FIG. 6A depicts a perspective view of a top side of the plate assembly260 of the mold-cavity system 200 of FIG. 4. The top portion 204 isbolted (securely connected) to the plate assembly 260. The plateassembly 260 defines a bore that receives the core portion 208. The tip261 of the core portion 208 extends outwardly from the plate assembly260, while a bottom portion of the core portion 208 remains within thebore defined by the plate assembly 260. The pressure-control system 126is connected to a side edge or a peripheral edge of the plate assembly260. Depicted in FIG. 6A is a non-limiting example in which two coreportions 208 are connected to respective pressure-control systems 126.It will be appreciated that it is possible to adapt or vary theconfiguration depicted in FIG. 6A such that a single pressure-controlsystem 126 may control two or more core portions 208.

FIG. 6B depicts a perspective view of a bottom side of the plateassembly 260 of the mold-cavity system 200 of FIG. 4. The plate assembly260 is formed or machined so that the plate assembly 260 accommodatesthe pressure-control system 126. FIG. 6B depicts the pressure-controlsystem 126. FIG. 6B recessed into the plate assembly 260.

FIG. 6C depicts a perspective view of the pressure-control system 126 ofFIG. 6A. For convenience, the plate assembly 260 has been removed so asto permit a clearer view of the pressure-control system 126. Thepressure-control system 126 includes: (i) a housing 150, (ii) a link156, (iii) a wedge 157, and (iv) a coupler 158. The housing 150 definesor provides a housing inlet 262 and a housing outlet 263, both of whichare used to receive and expel a hydraulic fluid, respectively. A bolt254 is used to connect the pressure-control system 126 to the plateassembly 260 (which is depicted in FIG. 6A). The link 156 extends outfrom the housing 150, and the link 156 connects with the wedge 157. Thecoupler 158 couples the wedge 157 with the core portion 208 of themold-cavity system 200. The coupler 158 abuts a surface of the plateassembly 260, and to locate or register the coupler 158 to the plateassembly 260, a locating device 264 (such as a pin) is received by thecoupler 158, and the plate assembly 260 includes a bore that alsoreceives the locating device 264. The coupler 158 defines bores thateach receives respective bolts 254, and the bolts 254 are used tosecurely connect the coupler 158 to the plate assembly 260. The coupler158 defines a wedge-receiving groove 265 that faces the plate assembly260, and the wedge-receiving groove 265 receives, at least in part, thewedge 157. The wedge 157 presents a surface 266 (which is tapered orcammed) that touches the bottom face 256 (depicted in FIG. 5E) of thecore portion 208. The wedge 157 is slidable relative to the bottom face256 of the core portion 208. it will be appreciated that the wedge 157and the coupler 158 and the core portion 208 are made of suitablewear-resistant materials. A locating device 264 (also called a pin)extends from the core portion 208. A groove (not depicted) is defined bythe plate assembly 260, and the grove slidably receives the locatingdevice 264 that extends from the core portion 208, and the locatingdevice 264 permits linear movement of the core portion 208, and thislinear movement is along a direction that is aligned substantiallyperpendicular relative to the alignment of the wedge 157. The locatingdevice 264 of the core portion 208 permits slidable movement of the coreportion 208 relative to the top portion 204 (the top portion 204 issecurely connected to the plate assembly 260 depicted in FIG. 6A).

The pressure-control system 126 operates, generally, in accordance withthe following approach: in operation, (i) while the mold cavity 213 isbeing filled, under pressure, with the molding material and before themold gate 216 is shut, the pressure-control system 126 is actuated so asto apply pressure to the core portion 208, so that the mold cavity 213maintains a predefined volume. After the mold gate 216 is shut so as toisolate the mold cavity 213 from the stream of molding material, thepressure-control system 126 is deactuated or de-energized so as toremove pressure to the core portion 208, so that the volume of the moldcavity 213 becomes relatively larger and in this manner there is apressure reduction realized in the mold cavity 213 after the mold gate216 is shut or closed.

In operation, the pressure-control system 126 operates under thefollowing operational modes: (i) an increase-pressure mode, or (ii) adecrease-pressure mode.

In the decrease-pressure mode, the pressure-control system 126 isactuated so that the link 156 is moved toward the housing 150, and inresponse the link 156 moves the wedge 157 toward the housing 150, sothat the surface 266 of the wedge 157 moves away from the bottom face256 of the core portion 208, and in this manner the spring 252 (depictedin FIGS. 5C and 5D) pushes the core portion 208 away from the topportion 204. The decrease-pressure mode is enabled or executed after themold gate 216 (depicted in FIG. 4) is held shut so as to isolate themold cavity 213 (isolating the mold cavity 213 means that the moldcavity 213 is fluidly disconnected from the melt stream associated withthe melt-preparation system 128, which is depicted in FIG. 3), and inthis manner the volume of the mold cavity 213 (also depicted in FIG. 4)of the mold-cavity system 200 becomes larger; since (i) the mold gate216 is held shut during the decrease-pressure mode, and (ii) the volumeof the mold cavity 213 is increased, then the pressure in the moldcavity 213 becomes decreased, which is required in accordance withmold-unpack instructions 520 that is depicted in FIG. 7.

In the increase-pressure mode, the pressure-control system 126 isactuated so that the link 156 is moved outwardly of the housing 150, andin response the link 156 moves the wedge 157 away from the housing 150,so that the surface 266 of the wedge 157 moves towards and against thebottom face 256 of the core portion 208, so that the spring 252 becomescompressed because the core portion 208 is urged to move toward the topportion 204.

It will be appreciated that the increase-pressure mode may be used withdifferent instructions of the set of controller-executable instructions500, which is depicted in FIG. 7, in accordance with the followingoptions:

A first option is to use or enable or execute the increase-pressure modebefore the mold gate 216 (depicted in FIG. 4) is shut and while the moldcavity 213 remains not isolated (that is, the mold cavity 213 remainsfluidly connected with the melt stream associated with themelt-preparation system 128, which is depicted in FIG. 3); in thismanner, the volume of the mold cavity 213 (depicted in FIG. 4) of themold-cavity system 200 becomes smaller; since (i) the mold gate 216 isheld open during the decrease-pressure mode, and the melt-preparationsystem 128 continues to apply pressure to pack out the mold cavity 213,and (ii) the volume of the mold cavity 213 is decreased, then thepressure in the mold cavity 213 becomes increased, which is required inaccordance with a hold instructions 530, which is depicted in FIG. 7. Itwill be appreciated that the melt-preparation system 128 continues toapply pressure to pack out the mold cavity 213 while the mold cavity 213remains not isolated (that is, the mold gate 216 is held open for thiscase) in the following manner, (by way of example): the screw assembly145 located in the barrel assembly 142 is urged forwardly so as tomaintain pressure on the melt located in the mold cavity 213 (since themold gate 216 is held open for this case), and this arrangement avoidsthe resin to become pushed back from the mold cavity 213 back into thehot-runner system 300 as a result of the mold gate 216 being held openas the core portion 208 is advanced to reduce the cavity volume of themold-cavity system 200. It will be appreciated that for this case, thereis some other blockage located upstream in the melt stream (to realize apacking process for this case).

A second option is to use or enable or execute the increase-pressuremode after the mold gate 216 (depicted in FIG. 4) is shut and the moldcavity 213 becomes isolated (that is, the mold cavity 213 is fluidlydisconnected from the melt stream associated with the melt-preparationsystem 128, which is depicted in FIG. 3); in this manner, the volume ofthe mold cavity 213 (depicted in FIG. 4) of the mold-cavity system 200becomes smaller; since (i) the mold gate 216 is held shut during thedecrease-pressure mode, and (ii) the volume of the mold cavity 213 isdecreased, then the pressure in the mold cavity 213 becomes increased,which is required in accordance with a mold-volume reductioninstructions 540, which is depicted in FIG. 7.

FIG. 6D depicts a perspective cross-sectional view of thepressure-control system 126, which further includes: (i) a hydraulicpiston 151, (ii) a chamber 152, (iii) a stop 153, and (iv) a seal 154.The housing 150 receives the hydraulic piston 151. The chamber 152 isdefined between the housing 150 and the hydraulic piston 151. The stop153 is received at one end of the housing 150 so as to limit the travelof the hydraulic piston 151. The seal 154 is received in the end of thehousing 150 and the seal 154 is used to prevent leakage of a hydraulicfluid received in the chamber 152. Movement of the core portion 208occurs within the top portion 204 (also called a lock ring). Inaccordance with a non-limiting example, the wedge 157 is used tohydraulically actuate movement of the core portion 208 of about 0.8millimeters (mm).

FIG. 6E depicts an exploded perspective view of the pressure-controlsystem 126. The wedge 157 includes a wedge body 267 that provides thesurface 266 (which is preferably a tapered surface), and the wedge body267 defines a wedge groove 268 that is sized so as to receive, at leastin part, the link 156. The link 156 includes a link body 269, a linkhead 270 that extends from the link body 269, and a link shoulder 271that is offset from the link head 270. The link head 270 is received inthe wedge groove 268, in this manner the link 156 is connected with thewedge 157. A housing cover 272 is attached with the housing 150, and thehousing cover 272 defines a central passageway that permits the link 156to be connected with the hydraulic piston 151 (as depicted in FIG. 6F).

FIG. 6F depicts a cross sectional perspective view of thepressure-control system 126, in an assembled state.

FIG. 6G depicts a partial cross-sectional view of the pressure-controlsystem 126. The plate assembly 260 includes a plate body 273. The platebody 273 defines a cooling circuit 275, which receives a cooling fluidin operation so as to maintain the temperature of the mold-cavity system200. The plate body 273 also defines a wedge cavity 274 that isconfigured or sized so as to receive and accommodate the wedge 157 andthe pressure-control system 126.

FIG. 7 depicts the schematic representation of the set ofcontroller-executable instructions 500 having instructions for operatingthe molding system 100 of FIG. 3. The set of controller-executableinstructions 500 includes (but is not limited to): mold-unpackinstructions 520. The set of controller-executable instructions 500 alsoincludes (but is not limited to) other instructions, such as: (i)melt-preparation instructions 502, (ii) mold-close instructions 504,(iii) mold-lock instructions 506, (iv) tonnage-engage instructions 508,(v) melt-stream connection instructions 510, (vi) mold-injectioninstructions 512, (vii) mold-pack instructions 514, (viii) melt-streamdisconnection instructions 516, (ix) heat-reduction instructions 518,(x) tonnage-disengage instructions 522, (xi) mold-unlock instructions524 and, (xii) mold-open instructions 526. It will be appreciated thatthe instructions 500 may be executed either in a parallel manner or aserial manner as known to those skilled in the art of processors.

The melt-preparation instructions 502 include instructing the controller160 to control the melt-preparation system 128, which is depicted inFIG. 3, to convert the molding material 101 into a stream offlowable-molding material. The melt-preparation instructions 502 may beexecuted by actuating the melt-preparation system 128 (also called anextruder, etc) having the screw assembly 145 in the barrel assembly 142that is connected to the hopper 140 configured to receive granules ofthe molding material 101. The screw assembly 145 rotates in the barrelassembly 142 so as to convert the molding material 101 into the streamof flowable-molding material. The barrel assembly 142 has the machinenozzle 144 connected with the mold-cavity system 200, either via: (i) ahot-sprue apparatus (for the case where a single cavity is to be filled,under pressure, with the stream of flowable-molding material), or (ii) ahot-runner system (for the case where multiple cavities need to befilled, under pressure, with the stream of flowable-molding material).It will be appreciated that the stream of flowable-molding material doesnot flow in a continuous manner but in an intermittent (on and off)manner.

The mold-close instructions 504 include instructing the controller 160to control the platen actuator 120, which is depicted in FIG. 3, to movethe movable platen 104 toward the stationary platen 102 thereby shuttingthe mold-cavity system 200 in a closed or shut state, and once closedthe mold-cavity system 200 defines the mold cavity 213.

The mold-lock instructions 506 include instructing the controller 160 tocontrol the bar locks 121, which are depicted in FIG. 3, to lock themovable platen 104 and the platen bars 106 so that the mold-cavitysystem 200 is locked, and in effect the portions of the mold-cavitysystem 200 do not move relative to each other when the mold-cavitysystem 200 is injected, under pressure, with the stream offlowable-molding material. The mold-lock instructions 506 may beexecuted by engaging the bar locks 121 so that the platens 102, 104 donot move relative to each other; specifically, this arrangement may beachieved, for example, by locking the platen bars 106 to the movableplaten 104.

The tonnage-engage instructions 508 include instructing the controller160 to control the clamp assemblies 122 (depicted in FIG. 3) to applythe clamp tonnage to the mold-cavity system 200 via the platen bars 106after the mold-cavity system 200 is closed shut and locked. Thetonnage-engage instructions 508 may be executed by pressurizing theclamp assemblies 122 to apply the clamp tonnage to the mold-cavitysystem 200 via the platens 102, 104 and the platen bars 106.

The melt-stream connection instructions 510 include instructing thecontroller 160 to control the melt-preparation system 128 (depicted inFIG. 3) to connect the mold-cavity system 200 to the stream offlowable-molding material, so that the stream of flowable-moldingmaterial may flow into the mold-cavity system 200. The melt-streamconnection instructions 510 may be executed by opening the mold gate 216leading into the mold-cavity system 200.

The mold-injection instructions 512 include instructing the controller160 to control the melt-preparation system 128 (depicted in FIG. 3) toinject a portion of the stream of flowable-molding material into themold-cavity system 200 while the clamp tonnage maintains the mold-cavitysystem 200 closed. The mold-injection instructions 512 may be executedby translating the screw of the screw assembly 145 of themelt-preparation system 128 toward the stationary platen 102.

The mold-pack instructions 514 include instructing the controller 160 tocontrol any one of the following options: (option i) themelt-preparation system 128, which is depicted in FIG. 3, or (option ii)the melt-preparation system 128 and the pressure-control system 126(depicted in FIG. 3) to apply an additional pressure to the moldingmaterial 101 contained in the mold-cavity system 200 while the moldingmaterial 101 becomes cooled, at least in part, in the mold-cavity system200. The mold-pack instructions 514 are executed while the mold gate 216is open (specifically, the mold-pack instructions 514 are executedbefore the mold gate 216 is closed). The purpose of the mold-packinstructions 514 is to compensate for shrinkage of the molding materialheld in the mold cavity 213 as a result of the molding material coolingdown. For option (i), the melt-preparation system 128 applies theadditional pressure to the molding material 101 contained in themold-cavity system 200 while the mold gate 216 is held open by forcingthe screw assembly 145 to apply additional pressure to the moldingmaterial. For option (ii), both the melt-preparation system 128 and thepressure-control system 126 to apply the additional pressure to themolding material 101 contained in the mold-cavity system 200 while themold gate 216 is held open.

The melt-stream disconnection instructions 516 include instructing thecontroller 160 to control the melt-preparation system 128 (depicted inFIG. 3) to disconnect the mold-cavity system 200 from the stream offlowable-molding material; in this manner the mold-cavity system 200becomes isolated from the stream of flowable-molding material after themold-cavity system 200 has received the portion of the stream offlowable-molding material (and the molding material in the mold cavity213 has been packed in before the mold gate 216 is closed). Themelt-stream disconnection instructions 516 may be executed by closingthe mold gate 216 by using gate valves, gate nozzles, etc.

The heat-reduction instructions 518 include instructing the controller160 to control the mold-cooling system 124 (depicted in FIG. 4) toremove heat from the molding material 101 received in the mold-cavitysystem 200 after the mold-cavity system 200 has been disconnected fromthe stream of flowable-molding material (so that the mold-cavity system200 becomes isolated from the stream of flowable-molding material); inresponse to the above instruction, solidification of the moldingmaterial 101 occurs in a gate portion 212 of the mold-cavity system 200so that the molded article 103 may be removed from the mold cavity 213of the mold-cavity system 200.

The mold-unpack instructions 520 include instructing the controller 160to control the pressure-control system 126 to reduce, aftersolidification, at least in part, of the molding material 101 that islocated in a nub region 214 of the mold-cavity system 200, internalpressure of the molding material 101 that is received in the mold-cavitysystem 200 while the mold-cavity system 200 remains isolated from astream of flowable-molding material. The reduction of the internalpressure of the molding material 101 that is received in the mold-cavitysystem 200 while the mold-cavity system 200 remains isolated from thestream is beyond any reduction of the internal pressure in the moldingmaterial 101 resulting from cooling of the molding material 101. Thetechnical effect is that the reduction in the internal pressure of themolding material 101 is enough to permit safe opening of the mold-cavitysystem 200 while permitting safe extraction of the molded article 103from the mold-cavity system 200.

The mold-unpack instructions 520 include instructing the controller 160to control the pressure-control system 126 (depicted in FIG. 6) toreduce, after solidification, at least in part, of the molding material101 located in a nub region 214 of the mold-cavity system 200, internalpressure of the molding material 101 received in the mold-cavity system200 beyond any reduction of the internal pressure in the moldingmaterial 101 as a result of cooling of the molding material 101; thereduction in the internal pressure of the molding material 101 is enoughto permit safe opening of the mold-cavity system 200. It will beappreciated that the mold-unpack instructions 520 may be executed oncethe nub region 214 has solidified sufficiently enough and the moldedarticle 103 may be solidified sufficiently enough so as to beconveniently removed from the mold-cavity system 200. If the mold-unpackinstructions 520 are executed before the molded article 103 has hadsufficient time to cool down, it may be too difficult to remove themolded article 103 article from the mold cavity 213 because the moldedarticle 103 has not become solidified enough for handling (that is,removal from the mold cavity 213). The mold-unpack instructions 520 maybe executed in accordance with an aggressive manner (as depicted in FIG.8B) or in accordance with a relaxed manner (as depicted in FIG. 8A),depending on the specifics of the geometry of the molded article 103,the mold-cavity system 200, the molding system 100, etc. It isrecommended to use a trial and error approach to find the mostappropriate time to begin execution of the mold-unpack instructions 520.

The tonnage-disengage instructions 522 include instructing thecontroller 160 to control the clamp assemblies 122 (depicted in FIG. 3)to disengage the clamp tonnage from the mold-cavity system 200. Thetonnage-disengage instructions 522 may be executed by to disengaging ordepressurizing the clamp assemblies 122 so as to stop application of theclamp tonnage to the mold-cavity system 200 via the platens 102, 104 andthe platen bars 106.

The mold-unlock instructions 524 include instructing the controller 160to control the bar locks 121 (depicted in FIG. 3) to unlock the movableplaten 104 and the platen bars 106 so that the mold-cavity system 200may be unlocked. The mold-unlock instructions 524 may be executed byunlocking the bar locks 121 so that the platens 102, 104 can be movedrelative to each other so as to separate the mold-cavity system 200 (andthus be able to remove the molded article 103 from the mold-cavitysystem 200).

The mold-open instructions 526 include instructing the controller 160 tocontrol the movable platen 104 (depicted in FIG. 3) to away from thestationary platen 102 thereby open the mold-cavity system 200, so that amolded part made in the mold-cavity system 200 may be removed from themold-cavity system 200 (either manually or by robot assembly, which isnot depicted but known).

FIG. 7 also depicts a first non-limiting variation 590 of the set ofcontroller-executable instructions 500: variations may be made to: (i)the mold-pack instructions 514, (ii) the melt-stream disconnectioninstructions 516, and (iii) the mold-unpack instructions 520.Specifically, the mold-pack instructions 514 may be varied so as tofurther include: hold instructions 530, and compensation instructions531.

In accordance with the first non-limiting variation 590, the holdinstructions 530 include instructing the controller 160 to control themolding system 100 to apply and hold the pressure to the moldingmaterial 101 being contained in the mold-cavity system 200 while themolding material 101 remains in a semi-solid state in the mold-cavitysystem 200; the hold instructions 530 may be executed by using the screwassembly 145 and maintaining the mold gate 216 open.

In accordance with the first non-limiting variation 590, thecompensation instructions 531 include instructing the controller 160 tocontrol the molding system 100 to inject an additional amount of themolding material 101 into the mold-cavity system 200 while the moldingmaterial 101 in the mold-cavity system 200 remains in the semi-solidstate; the additional amount of the molding material 101 compensates forshrinkage of the molding material 101 received in the mold-cavity system200; the compensation instructions 531 may be executed by using thescrew assembly 145, and keeping the mold gate 216 open; the compensationinstructions 531 are executed during the hold cycle. The hold cycle isused to compensate for density change of the molding material 101 byadding molding material 101, under the pressure, and permitting freezingof the nub portion 107 of the molded article 103. The nub portion 107 isalso called the “melt injection point”.

In accordance with the first non-limiting variation 590, the melt-streamdisconnection instructions 516 are executed: (i) after the mold-packinstructions 514 are executed so that the mold-cavity system 200 becomesisolated from the stream of flowable molding material, and (ii) beforethe mold-unpack instructions 520 are executed.

In accordance with the first non-limiting variation 590, the mold-unpackinstructions 520 further include: mold-volume increase instructions 532.The mold-volume increase instructions 532 include instructing thecontroller 160 to control the pressure-control system 126 of the moldingsystem 100 to increase the volume of the mold cavity 213 of themold-cavity system 200. Increasing the volume of the mold cavity 213reduces the pressure within the molding material 101 received in themold-cavity system 200 while: (i) the molding material 101 remains inthe semi-solid state in the mold-cavity system 200, and (ii) the moldcavity 213 remains isolated from the stream of the molding material; aninternal pressure of the molded article 103 is relieved by increasingeffective volume of the mold cavity 213, and a reduction of the pressureis accomplished by waiting for the molded article 103 to cool andactively increasing the volume of the mold cavity 213. The result is areduction in cycle time instead of waiting for the molded article 103 toshrink and cool off in the mold cavity 213. This arrangement provides anopportunity to decrease the pressure by allowing the volume of the moldcavity 213 to increase.

FIG. 7 also depicts a second non-limiting variant 592 of the set ofcontroller-executable instructions 500: variations may be made to: (i)the melt-stream disconnection instructions 516, (ii) the mold-packinstructions 514, and (iii) the mold-unpack instructions 520.

In accordance with the second non-limiting variant 592, the melt-streamdisconnection instructions 516 are executed: (i) before the mold-packinstructions are executed, and (ii) before the mold-unpack instructions520 are executed.

In accordance with the second non-limiting variant 592, the mold-packinstructions 514 further include mold-volume reduction instructions 540.The mold-volume reduction instructions 540 include instructing thecontroller 160 to control the pressure-control system 126 to decrease avolume of the mold cavity 213, so that the additional pressure isapplied to the molding material 101 received in the mold-cavity system200 while the molding material 101 remains in a semi-solid state in themold-cavity system 200, so that a size of the volume of the mold cavity213 is reduced and the molding material 101 located in the mold cavity213 is compressed, so that density of the molding material 101 locatedin the mold-cavity system 200 increases. This arrangement may beaccomplished, for example, by moving the core portion 208 toward themold gate 216, or other suitable mechanism, such as the mechanismsdescribed in U.S. Pat. No. 7,293,981.

In accordance with the second non-limiting variant 592, the mold-unpackinstructions 520 further include: mold-volume increase instructions 542.The mold-volume increase instructions 542 include instructing thecontroller 160 to control the pressure-control system 126 to increasethe volume of the mold cavity 213, so that an internal pressure of themolding material 101 contained in the mold-cavity system 200 is reducedwhile the molding material 101 remains in the semi-solid state in themold-cavity system 200, so that the molding material 101 located in themold-cavity system 200 becomes decompressed and the density of themolding material 101 decreases by expanding the volume of the moldcavity 213 before the mold-cavity system 200 is opened sufficiently soas to remove the molded article 103 and while the mold-cavity system 200remains isolated from the stream of the molding material 101. Forexample, this arrangement may be executed by having the core portion 208moving away from the mold gate 216 by using the mechanism described inU.S. Pat. No. 7,293,981.

FIGS. 8A and 8B depict schematic representations of graphs 401 and 501,respectively, having a cycle time 499 and a cycle time 599,respectively, superimposed on modified PVT curves 26, 28 of the PETresin of FIG. 2.

FIG. 8A depicts an example of using the set of controller-executableinstructions 500 of FIG. 7. The graph 420 has a molding operation 480superimposed on the modified PVT curves 26, 28 of FIG. 2. It will beappreciated that the graph 420 depicts flipped versions of the known PVTcurves 16, 18 depicted in FIG. 1. Specifically, the modified PVT curves26, 28 of FIG. 8A are the flipped versions (that is, flipped side toside) of the known PVT curves 16, 18 of FIG. 1, respectively. Thearrangement depicted in FIG. 8A permits the depiction of time asincreasing from the left side to the right side of the graph 420, andthat the cycle of the molding system 100 may be better understood whentime is depicted in this fashion. The graph 420 includes a time axis 418aligned along a horizontal direction of the graph 420 (that is, locatedalong the bottom side of the graph 420) and increasing from the leftside to the right side of FIG. 2. The graph 420 also includes thespecific volume axis 414 aligned along a vertical direction of the graph420 (that is, located on the left side of the graph 420), and increasingfrom the bottom side to the top side of FIG. 2. The graph 420 alsoincludes the temperature axis 412 aligned the horizontal direction ofthe graph 420 (that is, located along the top side of the graph 420),and increasing from the right side to the left side of FIG. 2.

Along the top of the graph 420 there is depicted the operations of themolding system 100 of FIG. 1. An operation 430 of the molding system 100includes (more or less): an operation 431, an operation 432, anoperation 433, an operation 434, an operation 435, an operation 436, anoperation 437, and an operation 438. The operations 431 to 438 aredepicted along the top side of FIG. 8A. The modified PVT curve 28 isused to describe the characteristics of the known PET resin during theoperations 431, 432, 433, 434 and 435.

The operation 431 includes closing a mold cavity. The operation 432includes locking the mold cavity shut and pressurizing a clamp assemblyso as to apply clamp tonnage to the mold assembly. The operation 433includes injecting melted resin into the mold cavity volume of the moldassembly; it will be appreciated that the operation 433 is sometimesknown as the “fill” cycle. The operation 434 includes slowly adding themelted resin to maintain a full cavity volume; it will be appreciatedthat the operation 434 is also known as the “hold” cycle. The operation434 provides compensation for the pressure change of the melt in themold cavity as the temperature drops for the molding material;specifically, as the temperature drops the tendency is for the pressureto drop but the operation 434 is used to increase of the density of themolten resin during the operation 434. Typically, at the end of the holdcycle or the operation 434, the operation 435 is executed; the operation435 includes shutting off the mold cavity or isolating the mold cavity;the operation 435 is sometimes referred to as the “shut-off cycle”.

The operation 435 includes moving a valve stem into a mold gate thatleads into the mold cavity, and the valve stem is used to stop furthermovement of the molten resin into and out from the mold cavity (via themold gate); when sufficient plastic density change has occurred, themolded part can be cooled down and removed from the mold cavity without,ideally, the molded article suffering from shrinkage relateddeformation. The operation 435 occurs at a point 421. Thecharacteristics of the PET resin during operation 436 are described by ahorizontally aligned line extending between a point 421 and a point 423.The point 423 is the point at which the mold-unpack instructions 520 areexecuted (so that the pressure in the mold cavity 213 is reduced afterthe mold gate 216 is closed and the mold cavity 213 is isolated form thestream of molding material). The specific volume of the molding materiallocated inside the mold cavity 213 will now increase from point 423 topoint 425 (as a result of the reduction in pressure). The point 421 andthe point 425 represent terminus points for a beginning and an ending ofthe operation 436. The horizontal line (that extends between the point421 and the point 423) is used is because a volume of the mold cavity213 does not increase or decrease during this portion of the operation436, and therefore the volume of the molten resin in the mold cavitydoes not change during this portion of the operation 436. However,between the point 423 and the point 425 the pressure in the mold cavity213 is decreased during this portion of the operation 436 (in sharpcontrast to the operation 36 of FIG. 2). At a region 441 the nub portion107 of the molded article 103 is considered to be solidified enough soas to permit safe removal of the molded article 103 from the mold cavity213 (the molded article 103 is removed in a hot condition from the moldcavity 213). At a region 439, the internal pressure of the moldedarticle 103 is near or at zero pressure, so that unlocking of the barlocks 121 would not cause the mold-cavity system 200 to inadvertentlypop open (thus avoiding potential damage to the mold-cavity system 200).

The modified PVT curve 26 is used to describe the characteristics of theknown PET resin during the operation 437 and the operation 438. Theoperation 437 includes depressurizing a clamp assembly and unlocking amold assembly. Since the internal pressure of the resin in the moldcavity has reduced to near zero or preferably zero pressure, there islittle or no danger of popping open the mold assembly (this is thepreferred situation so that the mold assembly is not inadvertentlydamaged by allowing it to pop open under pressure). The operation 438includes removing the molded article formed in the mold cavity, and thenpassing the molded article to a post mold cooling apparatus for furthertemperature reduction if so desired.

The cycle time 499 is depicted along the time axis 418, and it will beappreciated that the cycle time 499 is less than the known cycle time 30depicted in FIG. 2. It will be appreciated that the PVT curves and thecycle time 499 are not accurately drawn, but were drawn for illustrativepurposes for ease of explaining the concepts. Time 445 represents theamount of time saved or reduced in the cycle time in comparison to theknown cycle time 30 of FIG. 2. It will be appreciated that the amount oftime 443 (that is, the mold unpack time) used during the mold-unpackinstructions 520 can vary in accordance to the conditions that may berequired to ensure production of a molded article 103.

FIG. 8B represents a cycle time 599 (that is considered to be moreaggressive than the cycle time depicted in FIG. 8A) corresponding withan aggressive cycle operation 580 for the molding system 100 of FIG. 1.The points 521, 523 and 525 correspond with the points 421, 423 and 425of FIG. 8A, respectively. The point 523 is moved closer to the point 521(while the point 423 is further away from the point 421, in relativeterms). Similarly, the point 525 is moved closer to the point 521 (whilethe point 425 is further away from the point 421, in relative terms). Itwill be appreciated that under the scenario depicted in FIG. 8B, themolded article 103 removed from the mold cavity 213 will be hotter thanthe molded article 103 moved out from the mold cavity 213 under thescenario depicted in FIG. 8A. The cycle time 599 is depicted along thetime axis 519, and it will be appreciated that the cycle time 599 isless than the cycle time 499 depicted in FIG. 8A. Time 545 representsthe amount of time saved or reduced in the cycle time in comparison tothe known cycle time 30 of FIG. 2. It will be appreciated that theamount of time 543 used during the mold-unpack instructions 520 can varyin accordance to the conditions that may be required to ensureproduction of a molded article 103.

With reference to FIGS. 9A and 9B another non-limiting embodiment of thepresent invention will be described. FIG. 9A depicts a schematicrepresentation of the mold-cavity system 200 having the molding material101 after the gate is shut, and the nub region is beginning to freeze.The mold-cavity system 200 can be said to depict two parting lines(amongst others) between various components of a molding stack formingthe mold-cavity system 200. More specifically, there can be said to be a“primary parting line” which is depicted as the witness line 224,discussed in greater detail herein above. There is also depicted a“secondary parting line” depicted as the parting line 222, alsodiscussed herein above. Accordingly, it can be said that within thedepiction in FIGS. 9A and 9B, the primary parting line is definedbetween the cavity portion 210 and the neck portion 206 and thesecondary parting line is defined between the neck portion 206 and thetop portion 204.

FIG. 9B depicts the mold-cavity system 200 during initial stages of amold open operation. Generally speaking, the initial stages of the moldopen operation occur at the end of the so-called “process portion” ofthe molding cycle, which generally includes filling, holding and coolingoperations. As such, the initial stages of the mold open operation canbe implemented at the end of the in-mold cooling cycle or, in otherwords, at the end of the molding cycle when the mold-cavity system 200is ready to be opened.

More specifically, it can be seen that during the initial stages of themold open operation (but prior to unclamping of the mold-cavity system200 or, put another way, while maintaining at least some of the clampingforce), the stack components of the mold-cavity system 200 are firstseparated relative to the secondary parting line, while the primaryparting line is kept un-opened.

More specifically, prior to the release of clamp tonnage (i.e. whilemaintaining at least some of the clamp force), the controller 160 canactivate an ejector actuator (not depicted), which is configured toactuate a stripper assembly (not depicted) to which the neck portion 206of the mold-cavity system 200 is coupled to. As is known to those ofskill in the art, the ejector actuator can include push-pull or pushrods, coupled to suitable actuation structures. Within the embodimentsof the present invention, during the initial stages of mold opening, theprimary parting line can be kept un-opened by urging the neck portion206 towards the cavity portion 210, which can be achieved by activatingejector actuator to urge the neck portion 206 towards the cavity portion210. It is noted that within these embodiments of the present invention,the ejector actuator has to exert enough force to keep the neck portion206 urged towards the cavity portion 210. It is also noted that theejector actuator is actuated while at least a portion of the clamp forceis still being applied.

Within the architecture of FIGS. 9A and 9B, it is possible to implementa non-limiting embodiment of a method for opening the mold-cavity system200. It will be recalled that the controller 160 (schematically depictedin FIG. 9B, but which can be implemented similarly to the illustrationin FIG. 3) houses the controller-usable memory 162 tangibly embodying aset of controller-executable instructions 500 being configured to directthe controller 160.

Within these embodiments, the set of controller-executable instructions500 includes a mold-open instruction 902. The mold-open instruction 902is configured to cause activation of the ejector actuator to urge theneck portion 206 towards the cavity portion 210, such that to urge theneck portion 206 towards the cavity portion 210 in order to keep theprimary parting line un-opened. The mold-open instruction 902 is furtherconfigured to cause the mold-moving actuator (not depicted) to cause theclamp to reduce and/or cease applying clamp force.

It is noted that in some embodiments of the present invention, theactions of activation of ejector actuator and ceasing application of theclamp force can be triggered substantially simultaneously. In otherembodiments, one can be triggered after another, as long as the ejectoractuators are actuated and are capable of applying sufficient force tourge neck portion 206 towards the cavity portion 210 at the point intime when the clamp force falls below the plastic pressure in the moldedarticle 103 (i.e. before clamp force falls under plastic pressure valuethat is sufficient to cause the mold-cavity system 200 to open relativeto the primary parting line if the neck portion 206 was not being urgedtowards the cavity portion 210).

At a point in time thereafter and, more specifically, at the point intime when the clamp force is reduced sufficiently to enable safe openingof the mold-cavity system 200, the mold-open instruction 902 is furtherconfigured to cause the mold-cavity system 200 to open vis-à-vis theprimary parting line in a normal fashion to implement removal of themolded article 103 from the mold-cavity system 200. This, in turn, canbe implemented by either (a) de-activation in case of push rods or (b)activation in an opposite direction in case of the push pull rods of theejector actuator, to urge the neck portion 206 away from the cavityportion 210, at which point standard operation of the neck portion 206can be implemented, i.e. lateral opening of the split mold insertsforming the neck portion 206 by use of cams, servo motors or othersuitable actuators. A technical effect of these embodiments of thepresent invention may include fewer part defects attributable to themold-opening function. Another technical effect of these embodiments ofthe present invention may include reduction of the internal pressureassociated with the molded article 103.

Even though embodiments of the present invention have been describedwith reference to actuating of ejector actuators, this needs not be soin every embodiment of the present invention. For example, in analternative embodiment of the present invention, a separate actuator(not depicted) can be used to urge neck portion 206 towards the cavityportion 210. An example of such a separate actuator may include, forexample, an actuator based on active material (such as piezo-electricactuator, an example of which is described in co-owned U.S. Pat. No.7,293,981 issued to Niewels on Nov. 13, 2007.

Within non-limiting embodiments described above, it is contemplated thatthe core portion 208 can be moved away from the cavity portion 210 inorder to execute various embodiments of the present invention. Thedegree of such movement will vary, depending on the specificimplementation. However, what is noteworthy is that the degree ofmovement within previously described embodiments is such that only somemolecules of the plastic of the molded article 103 that abut with thecore portion 208 will move relative to the core portion 208, whileothers of the molecules of the plastic of the molded article 103 thatabut with the core portion 208 will not move or, in a sense, they“stick” in their relative position on the core portion 208.

In alternative non-limiting embodiments of the present invention, it iscontemplated that the core portion 208 can be moved away from the cavityportion 210 by a distance sufficient to displace the totality ofmolecules of the plastic of the molded article 103 that abut with thecore portion 208 from their relative positioning during the processcycle, the displacement being in substantially the same direction. Thismovement can be executed while maintaining at least some of the clampingforce. For the avoidance of doubt, by term “maintaining at least someclamping force” inventors contemplate maintaining clamping force suchthat the sum of the clamping force and the friction between the moldedarticle 103 and the core portion 208 is less than the ejector force(i.e. force exerted by the ejector actuator).

This is illustrated in more detail with reference to FIG. 10A and FIG.10B, in which FIG. 10A depicts a schematic representation of themold-cavity system 200 having the molded article 103 with its moleculesbeing in a position relative to the core portion 208 which can begenerally called “positioning during the process cycle” and FIG. 10Bdepicts a schematic representation of the mold-cavity system 200 havingthe molded article 103 after the core portion 208 has been moved awayfrom the cavity portion 210 by a distance sufficient to displace thetotality of molecules of the plastic of the molded article 103 that abutwith the core portion 208 from their relative positioning during theprocess cycle, the displacement being in substantially the samedirection (this direction of displacement being right-bound as viewed inFIG. 10B). It is noted that within this illustration, the mold-cavitysystem 200 has been effectively opened relative to what was referredbefore as the “secondary parting line”. However, this needs not be so inevery embodiment of the present invention. For example, in alternativeembodiments of the present invention, the mold-cavity system 200 can beopened similarly to the illustration in FIGS. 5A and 5B.

Effectively, by executing this movement, a part pre-eject function canbe executed, while the molded article 103 maintains most contact withthe cavity portion 210 and the neck portion 206. A specific technicaleffect attributable to these embodiments of the present invention mayinclude avoidance of part defect known as “rolled necks” (which is aname used for certain deformations to the neck finish of the moldedarticle 103), due at least partially to executing the pre-eject functionwhile maintaining the contact between the molded article 103 and theneck portion 206.

Within these embodiments of the present invention, the exact magnitudeof the travel distance will depend on several parameters, such as forexample, the inside draft angle associated with the molded article 103,i.e. the draft angle on the inner skin that abuts with the core portion208.

The description of the non-limiting embodiments provides non-limitingexamples of the present invention; these non-limiting examples do notlimit the scope of the claims of the present invention. The non-limitingembodiments described are within the scope of the claims of the presentinvention. The non-limiting embodiments described above may be: (i)adapted, modified and/or enhanced, as may be expected by persons skilledin the art, for specific conditions and/or functions, without departingfrom the scope of the claims herein, and/or (ii) further extended to avariety of other applications without departing from the scope of theclaims herein. It is understood that the non-limiting embodimentsillustrate the aspects of the present invention. Reference herein todetails and description of the non-limiting embodiments is not intendedto limit the scope of the claims of the present invention. Othernon-limiting embodiments, which may not have been described above, maybe within the scope of the appended claims. It is understood that: (i)the scope of the present invention is limited by the claims, (ii) theclaims themselves recite those features regarded as essential to thepresent invention, and (ii) preferable embodiments of the presentinvention are the subject of dependent claims. Therefore, what isprotected by way of letters patent is limited only by the scope of thefollowing claims:

1. A molding system (100) being configured to manufacture a moldedarticle (103) in a mold-cavity system (200) by using a molding material(101), the molding system (100) comprising: a pressure-control system(126) being coupled with the mold-cavity system (200); and a controller(160) operatively coupling to the pressure-control system (126), thecontroller (160) having a controller-usable memory (162) tangiblyembodying a set of controller-executable instructions (500) beingconfigured to direct the controller (160), the set ofcontroller-executable instructions (500) including: mold-unpackinstructions (520), including instructing the controller (160) tocontrol the pressure-control system (126) to reduce, aftersolidification, at least in part, of the molding material (101) beinglocated in a nub region (214) of the mold-cavity system (200), internalpressure of the molding material (101) received in the mold-cavitysystem (200) while the mold-cavity system (200) remains isolated from astream of flowable-molding material, beyond any reduction of theinternal pressure in the molding material (101) resulting from coolingof the molding material (101), so that the reduction in the internalpressure of the molding material (101) is enough to permit safe openingof the mold-cavity system (200) while permitting safe extraction of themolded article (103) from the mold-cavity system (200).
 2. A moldingsystem (100) being configured to manufacture a molded article (103) byusing a mold-cavity system (200) and using a molding material (101), themolding system (100) comprising: a group of controllable systems (108),including: a mold-cooling system (124) being configured to couple withthe mold-cavity system (200); a pressure-control system (126) beingconfigured to couple with the mold-cavity system (200); amelt-preparation system (128) being configured to couple with themold-cavity system (200); and a controller (160) being operativelycoupling to the group of controllable systems (108), the controller(160) having a controller-usable memory (162) tangibly embodying a setof controller-executable instructions (500) being configured to directthe controller (160) to control operation of the molding system (100),the set of controller-executable instructions (500) including:melt-stream disconnection instructions (516), instructing the controller(160) to control the melt-preparation system (128) to disconnect themold-cavity system (200) from a stream of flowable-molding material, sothat the mold-cavity system (200) becomes isolated from the stream offlowable-molding material after the mold-cavity system (200) hasreceived a portion of the stream of flowable-molding material;heat-reduction instructions (518), instructing the controller (160) tocontrol the mold-cooling system (124) to remove heat from the moldingmaterial (101) being received in the mold-cavity system (200) after themold-cavity system (200) has been disconnected from the stream offlowable-molding material so that the mold-cavity system (200) becomesisolated from the stream of flowable-molding material, and in responsesolidification of the molding material (101) occurs in a gate portion(212) of the mold-cavity system (200) so that the molded article (103)may be removed from the mold-cavity system (200); and mold-unpackinstructions (520), including instructing the controller (160) tocontrol the pressure-control system (126) to reduce, aftersolidification, at least in part, of the molding material (101) beinglocated in a nub region (214) of the mold-cavity system (200), internalpressure of the molding material (101) received in the mold-cavitysystem (200) while the mold-cavity system (200) remains isolated fromthe stream of flowable-molding material, beyond any reduction of theinternal pressure in the molding material (101) resulting from coolingof the molding material (101), so that the reduction in the internalpressure of the molding material (101) is enough to permit safe openingof the mold-cavity system (200) while permitting safe extraction of themolded article (103) from the mold-cavity system (200).
 3. The moldingsystem (100) of claim 2, wherein: the set of controller-executableinstructions (500) further include: mold-pack instructions (514),instructing the controller (160) to control any one of: (i) themelt-preparation system (128), and (ii) the melt-preparation system(128) and the pressure-control system (126) to reduce a pressure to themolding material (101) being contained in the mold-cavity system (200)while the molding material (101) becomes cooled, at least in part, inthe mold-cavity system (200); the mold-pack instructions (514) include:hold instructions (530), instructing the controller (160) to control themolding system (100) to apply and hold the pressure to the moldingmaterial (101) being contained in the mold-cavity system (200) while themolding material (101) remains in a semi-solid state in the mold-cavitysystem (200); and compensation instructions (531), instructing thecontroller (160) to control the molding system (100) to inject anadditional amount of the molding material (101) into the mold-cavitysystem (200) while the molding material (101) in the mold-cavity system(200) remains in the semi-solid state, and the additional amount of themolding material (101) compensating for shrinkage of the moldingmaterial (101) being received in the mold-cavity system (200); themelt-stream disconnection instructions (516) are executed: (i) after themold-pack instructions (514) are executed so that the mold-cavity system(200) becomes isolated from the stream of flowable-molding material, and(ii) before the mold-unpack instructions (520) are executed; and themold-unpack instructions (520) further include: mold-volume increaseinstructions (532), instructing the controller (160) to control thepressure-control system (126) to increase a volume of a mold cavity(213) of the mold-cavity system (200), the mold cavity (213) receivingthe molding material (101), increasing the volume of the mold cavity(213) reduces the pressure within the molding material (101) beingreceived in the mold-cavity system (200) while: (i) the molding material(101) remains in the semi-solid state in the mold-cavity system (200),and (ii) the mold cavity (213) remains isolated from the stream of themolding material.
 4. The molding system (100) of claim 2, wherein: theset of controller-executable instructions (500) further include:mold-pack instructions (514), instructing the controller (160) tocontrol any one of: (i) the melt-preparation system (128), and (ii) themelt-preparation system (128) and the pressure-control system (126) toreduce a pressure to the molding material (101) being contained in themold-cavity system (200) while the molding material (101) becomescooled, at least in part, in the mold-cavity system (200); themelt-stream disconnection instructions (516) are executed: (i) beforethe mold-pack instructions (514) are executed, and (ii) before themold-unpack instructions (520) are executed; the mold-pack instructions(514) further include: mold-volume reduction instructions (540),instructing the controller (160) to control the pressure-control system(126) to decrease a volume of a mold cavity (213) of the mold-cavitysystem (200), the mold cavity (213) having the molding material (101),so that an additional pressure is applied to the molding material (101)being received in the mold-cavity system (200) while the moldingmaterial (101) remains in a semi-solid state in the mold-cavity system(200), so that the volume of the mold cavity (213) is reduced and themolding material (101) located in the mold cavity (213) is compressed,so that density of the molding material (101) located in the mold-cavitysystem (200) increases; and the mold-unpack instructions (520) furtherinclude: mold-volume increase instructions (542), instructing thecontroller (160) to control the pressure-control system (126) toincrease the volume of the mold cavity (213), so that the internalpressure of the molding material (101) being contained in themold-cavity system (200) is reduced while the molding material (101)remains in the semi-solid state in the mold-cavity system (200), so thatthe molding material (101) located in the mold-cavity system (200)becomes decompressed and the density of the molding material (101)decreases by expanding the volume of the mold cavity (213) before themold-cavity system (200) is opened sufficiently so as to remove themolded article (103) and while the mold-cavity system (200) remainsisolated from the stream of the molding material (101).
 5. A moldingsystem (100) being configured to manufacture a molded article (103) byusing a mold-cavity system (200) and using a molding material (101), themold-cavity system (200) having a stationary-mold assembly (201) and amovable-mold assembly (203), the molding system (100) comprising: ahot-runner system (300) being coupled with the stationary-mold assembly(200; a stationary platen (102) being configured to support thehot-runner system (300) and the stationary-mold assembly (201); amovable platen (104) being configured to support the movable-moldassembly (203), and being movable relative to the stationary platen(102); platen bars (106) operatively extending between the stationaryplaten (102) and the movable platen (104); a group of controllablesystems (108), including: a platen actuator (120) being coupled with themovable platen (104); bar locks (121) lockably coupling the platen bars(106) with the movable platen (104); clamp assemblies (122) beingcoupled with the platen bars (106), the clamp assemblies (122) beingconfigured to apply a clamp tonnage to the platen bars (106); amold-cooling system (124) being configured to couple with themold-cavity system (200); a pressure-control system (126) beingconfigured to couple with the mold-cavity system (200); amelt-preparation system (128) being configured to couple with themold-cavity system (200); and a controller (160) being operativelycoupling to the group of controllable systems (108), the controller(160) having a controller-usable memory (162) tangibly embodying a setof controller-executable instructions (500) being configured to directthe controller (160) to control operation of the molding system (100),the set of controller-executable instructions (500) including:melt-preparation instructions (502), including instructing thecontroller (160) to control the melt-preparation system (128) to convertthe molding material (101) into a stream of flowable-molding material;mold-close instructions (504), including instructing the controller(160) to control the platen actuator (120) to move the movable platen(104) toward the stationary platen (102) thereby shutting close themold-cavity system (200); mold-lock instructions (506), instructing thecontroller (160) to control the bar locks (121) to lock the movableplaten (104) and the platen bars (106) so that the mold-cavity system(200) is locked, so that portions of the mold-cavity system (200) do notmove relative to each other when the mold-cavity system (200) isinjected, under pressure, with the stream of flowable-molding material;tonnage-engage instructions (508), instructing the controller (160) tocontrol the clamp assemblies (122) to apply the clamp tonnage to themold-cavity system (200) via the platen bars (106) after the mold-cavitysystem (200) is closed shut and locked; melt-stream connectioninstructions (510), instructing the controller (160) to control themelt-preparation system (128) to connect the mold-cavity system (200) tothe stream of flowable-molding material, so that the stream offlowable-molding material may flow into the mold-cavity system (200);mold-injection instructions (512), instructing the controller (160) tocontrol the melt-preparation system (128) to inject a portion of thestream of flowable-molding material into the mold-cavity system (200)while the clamp tonnage maintains the mold-cavity system (200) closed;mold-pack instructions (514), instructing the controller (160) tocontrol any one of: (i) the melt-preparation system (128), and (ii) themelt-preparation system (128) and the pressure-control system (126) toreduce the pressure to the molding material (101) being contained in themold-cavity system (200) while the molding material (101) becomescooled, at least in part, in the mold-cavity system (200); melt-streamdisconnection instructions (516), instructing the controller (160) tocontrol the melt-preparation system (128) to disconnect the mold-cavitysystem (200) from the stream of flowable-molding material, so that themold-cavity system (200) becomes isolated from the stream offlowable-molding material after the mold-cavity system (200) hasreceived the portion of the stream of flowable-molding material;heat-reduction instructions (518), instructing the controller (160) tocontrol the mold-cooling system (124) to remove heat from the moldingmaterial (101) being received in the mold-cavity system (200) after themold-cavity system (200) has been disconnected from the stream offlowable-molding material so that the mold-cavity system (200) becomesisolated from the stream of flowable-molding material, and in responsesolidification of the molding material (101) occurs in a gate portion(212) of the mold-cavity system (200) so that the molded article (103)may be removed from the mold-cavity system (200); mold-unpackinstructions (520), including instructing the controller (160) tocontrol the pressure-control system (126) to reduce, aftersolidification, at least in part, of the molding material (101) beinglocated in a nub region (214) of the mold-cavity system (200), internalpressure of the molding material (101) received in the mold-cavitysystem (200) while the mold-cavity system (200) remains isolated fromthe stream of flowable-molding material, beyond any reduction of theinternal pressure in the molding material (101) resulting from coolingof the molding material (101), so that the reduction in the internalpressure of the molding material (101) is enough to permit safe openingof the mold-cavity system (200) while permitting safe extraction of themolded article (103) from the mold-cavity system (200);tonnage-disengage instructions (522), instructing the controller (160)to control the clamp assemblies (122) to disengage the clamp tonnagefrom the mold-cavity system (200); mold-unlock instructions (524),instructing the controller (160) to control the bar locks (121) tounlock the movable platen (104) and the platen bars (106) so that themold-cavity system (200) is unlocked; and mold-open instructions (526),instructing the controller (160) to control the movable platen (104) toaway from the stationary platen (102) thereby opening the mold-cavitysystem (200), so that a molded part made in the mold-cavity system (200)may be removed from the mold-cavity system (200).
 6. The molding system(100) of claim 5, wherein: the mold-pack instructions (514) furtherinclude: hold instructions (530), instructing the controller (160) tocontrol the molding system (100) to apply and hold the pressure to themolding material (101) being contained in the mold-cavity system (200)while the molding material (101) remains in a semi-solid state in themold-cavity system (200); and compensation instructions (531),instructing the controller (160) to control the molding system (100) toinject an additional amount of the molding material (101) into themold-cavity system (200) while the molding material (101) in themold-cavity system (200) remains in the semi-solid state, and theadditional amount of the molding material (101) compensating forshrinkage of the molding material (101) being received in themold-cavity system (200); the melt-stream disconnection instructions(516) are executed: (i) after the mold-pack instructions (514) areexecuted so that the mold-cavity system (200) becomes isolated from thestream of flowable-molding material, and (ii) before the mold-unpackinstructions (520) are executed; and the mold-unpack instructions (520)further include: mold-volume increase instructions (532), instructingthe controller (160) to control the pressure-control system (126) toincrease a volume of a mold cavity (213) of the mold-cavity system(200), the mold cavity (213) receiving the molding material (101),increasing the volume of the mold cavity (213) reduces the pressurewithin the molding material (101) being received in the mold-cavitysystem (200) while: (i) the molding material (101) remains in thesemi-solid state in the mold-cavity system (200), and (ii) the moldcavity (213) remains isolated from the stream of the molding material.7. The molding system (100) of claim 5, wherein: the melt-streamdisconnection instructions (516) are executed: (i) before the mold-packinstructions (514) are executed, and (ii) before the mold-unpackinstructions (520) are executed; the mold-pack instructions (514)further include: mold-volume reduction instructions (540), instructingthe controller (160) to control the pressure-control system (126) todecrease a volume of a mold cavity (213) of the mold-cavity system(200), the mold cavity (213) having the molding material (101), so thatadditional pressure is applied to the molding material (101) beingreceived in the mold-cavity system (200) while the molding material(101) remains in a semi-solid state in the mold-cavity system (200), sothat the volume of the mold cavity (213) is reduced and the moldingmaterial (101) located in the mold cavity (213) is compressed, so thatdensity of the molding material (101) located in the mold-cavity system(200) increases; and the mold-unpack instructions (520) further include:mold-volume increase instructions (542), instructing the controller(160) to control the pressure-control system (126) to increase thevolume of the mold cavity (213), so that the internal pressure of themolding material (101) being contained in the mold-cavity system (200)is reduced while the molding material (101) remains in the semi-solidstate in the mold-cavity system (200), so that the molding material(101) located in the mold-cavity system (200) becomes decompressed andthe density of the molding material (101) decreases by expanding thevolume of the mold cavity (213) before the mold-cavity system (200) isopened sufficiently so as to remove the molded article (103) and whilethe mold-cavity system (200) remains isolated from the stream of themolding material (101).
 8. A controller (160) for use with a moldingsystem (100) being configured to manufacture a molded article (103) in amold-cavity system (200) by using a molding material (101), the moldingsystem (100) including a group of controllable systems (108) including apressure-control system (126) being: (i) coupled with the mold-cavitysystem (200), and (ii) being operatively coupled to the group ofcontrollable systems (108), the controller (160) comprising: acontroller-usable memory (162) tangibly embodying a set ofcontroller-executable instructions (500) being configured to direct thecontroller (160) to control operation of the molding system (100), theset of controller-executable instructions (500) including: mold-unpackinstructions (520), including instructing the controller (160) tocontrol the pressure-control system (126) to reduce, aftersolidification, at least in part, of the molding material (101) beinglocated in a nub region (214) of the mold-cavity system (200), internalpressure of the molding material (101) received in the mold-cavitysystem (200) while the mold-cavity system (200) remains isolated from astream of flowable-molding material, beyond any reduction of theinternal pressure in the molding material (101) resulting from coolingof the molding material (101), so that the reduction in the internalpressure of the molding material (101) is enough to permit safe openingof the mold-cavity system (200) while permitting safe extraction of themolded article (103) from the mold-cavity system (200).
 9. Acontroller-usable memory (162) for use with a controller (160), thecontroller (160) for use with a molding system (100) being configured tomanufacture a molded article (103) in a mold-cavity system (200) byusing a molding material (101), the molding system (100) including agroup of controllable systems (108) including a pressure-control system(126) being: (i) coupled with the mold-cavity system (200), and (ii)being operatively coupled to the group of controllable systems (108),the controller-usable memory (162) comprising: a set ofcontroller-executable instructions (500) being tangibly embodied in thecontroller-usable memory (162), and being configured to direct thecontroller (160) to control operation of the molding system (100), theset of controller-executable instructions (500) including: mold-unpackinstructions (520), including instructing the controller (160) tocontrol the pressure-control system (126) to reduce, aftersolidification, at least in part, of the molding material (101) beinglocated in a nub region (214) of the mold-cavity system (200), internalpressure of the molding material (101) received in the mold-cavitysystem (200) while the mold-cavity system (200) remains isolated from astream of flowable-molding material, beyond any reduction of theinternal pressure in the molding material (101) resulting from coolingof the molding material (101), so that the reduction in the internalpressure of the molding material (101) is enough to permit safe openingof the mold-cavity system (200) while permitting safe extraction of themolded article (103) from the mold-cavity system (200).
 10. A method ofoperating a molding system (100) being configured to manufacture amolded article (103) in a mold-cavity system (200) by using a moldingmaterial (101), the molding system (100) having a pressure-controlsystem (126) being coupled with the mold-cavity system (200), the methodcomprising: controlling the pressure-control system (126) to reduce,after solidification, at least in part, of the molding material (101)being located in a nub region (214) of the mold-cavity system (200),internal pressure of the molding material (101) received in themold-cavity system (200) while the mold-cavity system (200) remainsisolated from a stream of flowable-molding material, beyond anyreduction of the internal pressure in the molding material (101)resulting from cooling of the molding material (101), so that thereduction in the internal pressure of the molding material (101) isenough to permit safe opening of the mold-cavity system (200) whilepermitting safe extraction of the molded article (103) from themold-cavity system (200).
 11. A molding system (100) being configured tomanufacture a molded article (103) by using a molding material (101),the molding system (100) comprising: a mold-cavity system (200) forforming, in use, the molded article (103); the mold-cavity system (200)including: a primary parting line (224) defined between a cavity portion(210) and a neck portion 206 and; a secondary parting line (222) definedbetween the neck portion (206) and a top portion (204); a controller(160) operatively coupling to the a mold-moving actuator, the controller(160) having a controller-usable memory (162) tangibly embodying a setof controller-executable instructions (500) being configured to directthe controller (160), the set of controller-executable instructionsincluding a mold open instruction (902) configured to: cause initialseparation of the top portion (204) and the neck portion (206) relativeto the secondary parting line, while keeping the primary parting lineun-opened, while maintaining at least some clamp force.
 12. The moldingsystem (100) of claim 11, to keep the primary line un-opened, themold-open instruction (902) is further configured to: activate anejector actuator to urge the neck portion (206) towards the cavityportion (210) during the initial separation; and cause a clamp to ceaseapplying clamp force.
 13. The molding system (100) of claim 12, whereinthe mold-open instruction (902) is configured to activate the ejectoractuator to urge the neck portion (206) towards the cavity portion (210)during the initial separation before it is configured to cause a clampto cease applying clamp force.
 14. The molding system (100) of claim 12,wherein the mold-open instruction (902) is configured to activate theejector actuator to urge the neck portion (206) towards the cavityportion (210) during the initial separation substantially simultaneouslyas it is configured to cause a clamp to cease applying clamp force. 15.The molding system (100) of claim 12, wherein the mold-open instruction(902) is configured to activate the ejector actuator to urge the neckportion (206) towards the cavity portion (210) during the initialseparation after it is configured to cause a clamp to cease applyingclamp force.
 16. The molding system (100) of claim 11, wherein themold-open instruction (902) is further configured to cause, at a pointin time after the initial separation, the cavity portion (210) and theneck portion (206) to open relative to the primary parting line toimplement removal of the molded article (103) from the mold-cavitysystem (200).
 17. A molding system (100) being configured to manufacturea molded article (103) by using a molding material (101), the moldingsystem (100) comprising: a mold-cavity system (200) for forming, in use,the molded article (103); the mold-cavity system (200) including: astationary-mold assembly (201) and a movable-mold assembly (203),defining therebetween a mold cavity; the movable-mold assembly (203)including: a base portion (202), a top portion (204), a neck portion(206); a core portion (208), the stationary-mold assembly (201)including: a cavity portion (210), and a gate portion (212), acontroller (160) operatively coupling to the a mold-moving actuator, thecontroller (160) having a controller-usable memory (162) tangiblyembodying a set of controller-executable instructions (500) beingconfigured to direct the controller (160), the set ofcontroller-executable instructions including a mold open instruction(902) configured to: cause relative movement between the core portion(208) and the cavity portion (210) by a distance sufficient to displacethe totality of molecules of plastic of the molded article (103) thatabut with the core portion (208) from their relative positioning duringa process cycle, the displacement being in substantially the samedirection, while maintaining at least some of the clamping force.